As a known color conversion table for converting an input color system into an output color system, JP-A-2009-188657 describes a technology of determining an ink volume serving as an output color system corresponding to a plurality of lattice points of an input color system by defining a quadratic form function corresponding to the plurality of lattice points as an objective function and by minimizing the objective function. (See also, JP-T-2007-511161, JP-T-2007-516663, and JP-T-2007-511175)